Aims to increase the basic knowledge on decadal behaviour of large coastal stretches, focusing on sub-aqueous morphologic developments. This" basic knowledge'covers a wide range of topics, eg the nature of the morphologic behaviour of large coastal stretches over a time span of decades and the relevant boundary conditions for the coastal behaviour on these scales. Another topic is the relationship between spatial scales and time scales in coastal behaviour. To obtain this type of knowledge, the decadal behaviour of the Holland coast is analysed.-from Author